https://uvadoc.uva.es/handle/10324/31665 BioEcoUVa - Otros Documentos (Monografías, Informes, Memorias, Documentos de Trabajo, etc) Sun, 12 Apr 2026 23:39:42 GMT 2026-04-12T23:39:42Z https://uvadoc.uva.es/handle/10324/39106 Horno microondas para el calentamiento de flujos continuos de Líquidos y semisólidos. Horno microondas aplicable industrialmente para el calentamiento de flujos continuos de líquidos y semisólidos, cuya cavidad resonante presenta una sección con arcos circulares que permiten la concentración de la radiación de microondas multimodal en su eje central; donde el horno dispone de guías de onda cilíndricas metálicas al corte a modo de filtros electromagnéticos que permiten el paso del tubo dieléctrico hueco y el producto a procesar impidiendo la radiación de microondas al exterior, sintonizadores dieléctricos y/o metálicos para el ajuste de la distribución multimodal de la energía en el interior de la cavidad, y soportes dieléctricos sin pérdidas; donde la energía de microondas se propaga a través de una guía de onda rectangular alimentada por un sistema generador de microondas; y donde dicha guía de onda se encuentra cortocircuitada al final de la misma y se comunica con la cavidad cuasicilíndrica a través de ranuras. Tue, 01 Jan 2019 00:00:00 GMT https://uvadoc.uva.es/handle/10324/39106 2019-01-01T00:00:00Z https://uvadoc.uva.es/handle/10324/35112 Three different bimetallic Ru:Ni catalysts supported on a mesoporous silica MCM-48 were prepared byconsecutive wet impregnations, with a total metal loading of ca. 3% (w w−1). Ru:Ni ratios spanned in therange of 0.15–1.39 (w w−1) and were compared with the corresponding monometallic Ni/MCM-48. Thecatalysts so prepared were characterized by X-Ray Diffraction, Transmission Electron Microscopy, adsorp-tion/desorption of N2, Temperature Programmed Reduction, NH3− TPD and Atomic Absorption, andtested in the liquid phase hydrogenation of d-glucose into sorbitol in the temperature range 120–140◦Cunder 2.5 MPa of H2pressure. Bimetallic catalysts with Ru:Ni ratios higher than 0.45 enhanced the cat-alytic behavior of the monometallic Ni/MCM-48 in the reaction, increasing the reaction rate and showingcomplete selectivity to sorbitol by minimizing the production of mannitol. Ru:Ni/MCM-48 (0.45) wasrecovered from the reaction media and tested for three reaction cycles, showing good stability under theselected experimental conditions. Sun, 01 Jan 2017 00:00:00 GMT https://uvadoc.uva.es/handle/10324/35112 2017-01-01T00:00:00Z https://uvadoc.uva.es/handle/10324/23523 The degradation of monosaccharides, though often undesired in lignocellulosic pretreatment, often lead to the formation of products with a higher value than the same sugars. In this chapter, detailed information related to monomers-based lignocellulosic biomass decomposition towards value added products using both water alone and water/CO2 mixture is showed. We will analyse the reaction mechanisms leading to the rupture of the oligomers into monosaccharaides, and then they breakage through dehydration reactions or aldol reactions. It will be demonstrated that CO2 plays a determinant role in catalysis of hydrolytic reactions that take place in aqueous media. The optimum conditions for obtaining different products will be discussed, also providing some indications on which configuration to adopt, for increasing the selectivity of some reactions with respect to others. Sun, 01 Jan 2017 00:00:00 GMT https://uvadoc.uva.es/handle/10324/23523 2017-01-01T00:00:00Z https://uvadoc.uva.es/handle/10324/23496 Most of the sorbitol processing at industrial scale is performed by hydrogenation of d-glucose using Raney–nickel catalysts. Noble metals (Ru, Rh, Pd and Pt) and non-noble metals (Fe, Ni, Cu or Co) have been used in hydrogenation reactions. Nickel catalysts have achieved a good piece of attention according to their low cost and moderate to good catalytic activity. Nevertheless, nickel catalysts are susceptible to show deactivation after its recycling due to leaching of the active nickel into the reaction media, sintering of the active metal and poisoning of metallic nickel surface. The current trend consists on the preparation of ruthenium catalysts, which show catalytic activities per mass of active metal 20 – 50 times higher in comparison with nickel. However, the high price of noble metals is the main drawback. Thus, the development of novel bimetallic nickel catalysts with comparable high activity to noble metal catalysts still remains a technological challenge. In this work, three bimetallic Ru:Ni catalysts supported on a mesoporous silica MCM-48 were prepared by consecutive wet impregnations, with a total metal loading of ca. 3% (w w−1). Ru:Ni ratios spanned in the range of 0.15–1.39 (w w−1) and were compared with the corresponding monometallic Ni/MCM-48. The catalysts so prepared were characterized by XRD, TEM, adsorption/desorption of N2, H2-TPR, NH3− TPD and Atomic Absorption, and tested in the liquid phase hydrogenation of d-glucose into sorbitol in the temperature range 120–140 ºC under 2.5 MPa of H2 pressure (Figure 1). Bimetallic catalysts with Ru:Ni ratios higher than 0.45 enhanced the catalytic behaviour of the monometallic Ni/MCM-48 in the reaction, increasing the reaction rate and showing complete selectivity to sorbitol by minimizing the production of mannitol. Ru:Ni/MCM-48 (0.45) was recovered from the reaction media and tested for three reaction cycles, showing good stability under the selected experimental conditions. Sun, 01 Jan 2017 00:00:00 GMT https://uvadoc.uva.es/handle/10324/23496 2017-01-01T00:00:00Z